In the past, pumps, and particularly multi-stage pumps, have been provided with some form of fluid by-pass or equalizing conduit extending from the seals on the inlet end of the pump to the seals on the discharge end of the pump so that the pressure on the seals will be substantially equal. Also, it has been necessary in the past to, in most instances, provide some form of cooling and flushing for the seals. This has ordinarily been accomplished by providing a completely external circuit through which fluid was delivered to the seals through a filter and some form of heat exchanger wherein the heat generated in the seals could be extracted.
The object of this invention is to provide an improved seal flushing and cooling system wherein the fluid being pumped is reduced in pressure and filtered within the pump so that it can be utilized as a flushing and cooling medium without further treatment. Furthermore, with the system described herein the use of the heat exchangers can be eliminated.